The originally described C2 typing technique has been modified to allow typing on ordinary electrofocusing equipment, without the use of specific C2-deficient serum. The modifications include prolonged electrofocusing time, iodine treatment of gels after focusing, and the use of low concentration normal human complement as “C2-lacking complement.”
In a Norwegian population sample C2 gene frequencies were: C21: = 0.97, C22: = 0.03, these frequencies fit well with those reported in other Caucasian populations.
C2-linkage relations and haplotype associations have been examined in an extensive Norwegian family material. No recombinations were found in 22 informative C2/HLA-B meioses and the rare C22 allele was accompanied by the HLA-Bw15 allele in 6 out of 7 instances. Our data therefore confirm the linkage of C2 to the HLA region loci, and we conclude that C2 is situated in close proximity to the HLA-B locus.